Lunettes is just like "eyeglasses" in English - they are both plural. The "s" at the end usually means that the word is plural, but there are exceptions.
There are many words like this in both languages. Sometimes they're both plural and sometimes the noun is plural in one language but not the other, such as les épinards = "spinach." This is just something you need to learn along with the new words.
Sign in to submit your answer
Don't have an account yet? Join today
Test your French to the CEFR standard